/Engine/Source/Runtime/Engine/Classes/Distributions/DistributionFloatUniformCurve.h
Get the incoming and outgoing tangent for the given subcurve and key. SubIndex must be within range ie >=0 and < NumSubCurves. KeyIndex must be within range ie >=0 and < NumKeys.
virtual void GetTangents ( int32 SubIndex, int32 KeyIndex, float & ArriveTangent, float & LeaveTangent ) const